Electric compressor

ABSTRACT

An electric compressor includes a compression mechanism, an electric motor, an inverter, a housing, and a cover attached to the housing to accommodate the inverter between the cover and the housing. The cover is constituted of a metal frame portion and a resin portion covering the frame portion to surround surfaces of the frame portion. 
     The frame portion has a plate-like portion and a peripheral wall portion extending from an outer peripheral edge of the plate-like portion toward the housing. The peripheral wall portion has concaves and convexes including at least one of a concave portion recessed in a thickness direction of the plate-like portion and a convex portion protruding in the thickness direction of the plate-like portion, at an end portion which is far from the plate-like portion. The resin portion is engaged with the concaves and convexes.

This nonprovisional application is based on Japanese Patent Application No. 2015-062522 filed on Mar. 25, 2015 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an electric compressor.

Description of the Background Art

Japanese Patent Laying-Open No. 2000-31606 is a prior art document which discloses a mold wiring board intended to prevent insulation deterioration due to peeling off, warpage, cracking, and the like of a molding resin based on thermal expansion and contraction between a metal frame and the resin.

In the mold wiring board described in Japanese Patent Laying-Open No. 2000-31606, the metal frame is embedded in the resin. A hole is formed in the metal frame, and resins above and below the metal frame are bonded in the shape of a bridge beam, through the hole.

SUMMARY OF THE INVENTION

In the mold wiring board described in Japanese Patent Laying-Open No. 2000-31606, the metal frame molded by punching a plate-like metal with a press die is embedded in the resin. Since the metal frame can have various shapes, it is necessary to set the arrangement of a portion where the resins are bonded in the shape of a bridge beam to correspond to the shape of the metal frame.

An object of the present invention is to provide an electric compressor which can suppress breakage of a resin member due to a difference in thermal expansion coefficient between a metal member and the resin member in a cover.

An electric compressor in accordance with the present invention includes a compression mechanism for compressing a fluid, an electric motor for driving the compression mechanism, an inverter for driving the electric motor, a housing for accommodating the compression mechanism and the electric motor, and a cover attached to the housing to accommodate the inverter between the cover and the housing. The cover is constituted of a metal frame portion and a resin portion covering the frame portion to surround surfaces of the frame portion. The frame portion has a plate-like portion and a peripheral wall portion extending from an outer peripheral edge of the plate-like portion toward the housing. The peripheral wall portion has concaves and convexes including at least one of a concave portion recessed in a thickness direction of the plate-like portion and a convex portion protruding in the thickness direction of the plate-like portion, at an end portion which is far from the plate-like portion. The resin portion is engaged with the concaves and convexes.

According to the present invention, breakage of a resin member due to a difference in thermal expansion coefficient between a metal member and the resin member in a cover can be suppressed.

The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an appearance of an electric compressor in accordance with a first embodiment of the present invention.

FIG. 2 is a perspective view showing an appearance of a cover included in the electric compressor in accordance with the first embodiment of the present invention.

FIG. 3 is a cross sectional view of the cover included in the electric compressor in accordance with the first embodiment of the present invention, viewed from the direction of arrows on a line in FIG. 2.

FIG. 4 is a perspective view showing an appearance of a frame portion of the cover included in the electric compressor in accordance with the first embodiment of the present invention.

FIG. 5 is a bottom view showing an appearance of the frame portion of the cover included in the electric compressor in accordance with the first embodiment of the present invention, viewed from the direction of an arrow V in FIG. 4.

FIG. 6 is a side view showing a shape of a peripheral wall portion of a frame portion of a cover included in an electric compressor in accordance with a modification of the first embodiment of the present invention.

FIG. 7 is a bottom view showing an appearance of a frame portion of a cover included in an electric compressor in accordance with a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an electric compressor in accordance with each embodiment of the present invention will be described with reference to the drawings. In the description below, identical or corresponding parts in the drawings will be designated by the same reference numerals, and the description thereof will not be repeated.

First Embodiment

FIG. 1 is a side view showing an appearance of an electric compressor in accordance with a first embodiment of the present invention. As shown in FIG. 1, an electric compressor 100 in accordance with the first embodiment of the present invention includes a compression mechanism 120 for compressing a fluid, an electric motor 130 for driving the compression mechanism 120, an inverter 140 for driving the electric motor 130, a housing 110 for accommodating the compression mechanism 120 and the electric motor 130, and a cover 150 attached to the housing 110 to accommodate the inverter 140 between the cover 150 and the housing 110.

The housing 110 includes a suction housing 112 in which a suction port (not shown) is formed, through which a refrigerant is suctioned from an external refrigerant circuit (not shown), and a discharge housing 111 in which a discharge port (not shown) is formed, through which the refrigerant is discharged.

In the present embodiment, each of the suction housing 112 and the discharge housing 111 has a bottomed cylindrical shape, and is made of, for example, a metal material such as aluminum. The cover 150 has a bottomed cylindrical shape, and is made of, for example, a metal material such as aluminum. The suction housing 112 accommodates the compression mechanism 120 and the electric motor 130.

The compression mechanism 120 compresses in a compression chamber the refrigerant suctioned through the suction port into the housing 110, and discharges the compressed refrigerant from the compression chamber through the discharge port. It should be noted that, as a concrete configuration of the compression mechanism 120, any configuration such as a scroll type, a piston type, or a vane type may be adopted.

The electric motor 130 is an electric motor driven with three-phase alternating current (AC) power, and drives the compression mechanism 120 by rotating a movable scroll. The electric motor 130 includes a rotor (not shown) having a rotating shaft, and a stator (not shown) covering the circumference of the rotor. The rotating shaft of the rotor is connected to the movable scroll. The stator has a stator coil, and is fixed to the suction housing 112.

Each of the suction housing 112, the discharge housing 111, and the cover 150 includes a bottom wall, and a peripheral wall standing from an outer peripheral edge of the bottom wall and having an annular shape. An axial direction of the suction housing 112 corresponds to an axial direction of the rotating shaft of the rotor.

An end portion 112 e of a peripheral wall 112 s of the suction housing 112 opposite to a bottom wall 112 b thereof is joined to an end portion 111 e of a peripheral wall 111 s of the discharge housing 111 opposite to a bottom wall 111 b thereof. An end portion 150 e of a peripheral wall 150 s of the cover 150 opposite to a bottom wall 150 b thereof is joined to an outer surface of the bottom wall 112 b of the suction housing 112.

The cover 150 is joined to the housing 110 by a fastening member, an adhesive, or the like. The inverter 140 for driving the electric motor 130 is accommodated in an inverter housing chamber defined by the outer surface of the bottom wall 112 b of the suction housing 112 and the cover 150.

In the present embodiment, the compression mechanism 120, the electric motor 130, and the inverter 140 are arranged in order of the compression mechanism 120, the electric motor 130, and the inverter 140, along the axial direction of the rotating shaft of the rotor. However, the arrangement of the inverter 140 is not limited thereto, and for example, the inverter 140 may be arranged outside the peripheral wall 112 s of the suction housing 112.

The inverter 140 performs control of rotation of the electric motor 130, and supply of power to the electric motor 130. The inverter 140 converts direct current (DC) power into AC power. The inverter 140 is electrically connected to the electric motor 130 through a cluster block and a hermetic terminal (not shown). Further, the inverter 140 is connected with a power supply cable for receiving power supply.

FIG. 2 is a perspective view showing an appearance of the cover included in the electric compressor in accordance with the first embodiment of the present invention.

FIG. 3 is a cross sectional view of the cover included in the electric compressor in accordance with the first embodiment of the present invention, viewed from the direction of arrows on a line in FIG. 2.

As shown in FIGS. 1 to 3, the cover 150 includes a plate-like portion 151 in the shape of a flat plate, a peripheral wall portion 152 extending from an outer peripheral edge of the plate-like portion 151 toward the housing 110, and a tubular first protruding portion 153 and a tubular second protruding portion 154 protruding from a surface of the plate-like portion 151 opposite to a surface thereof provided with the peripheral wall portion 152. The plate-like portion 151 is provided with three counterbored portions 155 for tightening headed bolts (not shown) for attaching the cover 150 to the housing 110.

The first protruding portion 153 is a connector for connecting the inverter 140 with the power supply cable. The second protruding portion 154 is a connector for connecting signal lines for detecting the states of the electric motor 130 and the compression mechanism 120.

As shown in FIG. 3, the cover 150 is constituted of a metal frame portion 160 and a resin portion 170 covering the frame portion 160 to surround surfaces of the frame portion 160. The frame portion 160 serves as an electromagnetic shield. The frame portion 160 is made of an aluminum-based metal material. However, the material for the frame portion 160 is not limited to an aluminum-based metal material, and may be another metal material. The resin portion 170 is made of an epoxy resin. However, the material for the resin portion 170 is not limited to an epoxy resin, and may be another insulating resin material.

In the present embodiment, the resin portion 170 is integrally constituted by bonding an inner member and an outer member with each other using a resin-based adhesive, in a state where these members are assembled on the frame portion 160, the inner member being molded beforehand to have a shape that follows an inner surface of the frame portion 160 (i.e., of two surfaces of the frame portion 160 extending in a direction intersecting with a thickness direction, a surface facing the inverter housing chamber), the outer member being molded beforehand to have a shape that follows an outer surface of the frame portion 160 (i.e., of the two surfaces of the frame portion 160 extending in the direction intersecting with the thickness direction, a surface opposite to the surface facing the inverter housing chamber). The inner member and the outer member are bonded with each other at an end portion of the peripheral wall portion 162 which is far from a plate-like portion 161, which is described later. However, the method for forming the resin portion 170 is not limited to the method described above, and the resin portion 170 may be integrally constituted by insert-molding the frame portion 160.

FIG. 4 is a perspective view showing an appearance of the frame portion of the cover included in the electric compressor in accordance with the first embodiment of the present invention. FIG. 5 is a bottom view showing an appearance of the frame portion of the cover included in the electric compressor in accordance with the first embodiment of the present invention, viewed from the direction of an arrow V in FIG. 4.

As shown in FIGS. 4 and 5, the frame portion 160 includes a plate-like portion 161, a peripheral wall portion 162 extending from an outer peripheral edge of the plate-like portion 161 toward the housing, and a tubular first protruding portion 163 and a tubular second protruding portion 164 protruding from a surface of the plate-like portion 161 opposite to a surface thereof provided with the peripheral wall portion 162. The plate-like portion 161 is provided with three counterbored portions 165.

The plate-like portion 161 in accordance with the present embodiment has a shape formed by connecting a portion of a rectangular portion 161 r having a rectangular shape and a portion of a circular portion 161 c having a circular shape.

The contour of the plate-like portion 161 when viewed in a plan view includes one long side and two short sides which constitute the contour (outer peripheral edge) of the rectangular portion 161 r, and an arc connecting end portions of the two short sides of the rectangular portion 161 r which constitutes the contour (outer peripheral edge) of the circular portion.

The peripheral wall portion 162 in accordance with the present embodiment extends from the outer peripheral edge of the plate-like portion 161 toward the housing. In other words, the peripheral wall portion 162 extends in a thickness direction of the plate-like portion 161. The peripheral wall portion 162 is constituted of a first peripheral wall portion 162 c in the shape of an arc extending from an outer peripheral edge of the circular portion 161 c, a second peripheral wall portion 162 r in the shape of a rectangular flat plate extending from an outer peripheral edge of the long side of the rectangular portion 161 r, and a third peripheral wall portion 162 p and a fourth peripheral wall portion 162 q extending from outer peripheral edges of the two short sides of the rectangular portion 161 r.

The first to fourth peripheral wall portions 162 c, 162 r, 162 p, 162 q are provided with concave portions 162 n at an end portion which is far from the plate-like portion 161. Each concave portion 162 n is formed by providing a notch in the end portion which is far from the plate-like portion 161. That is, the peripheral wall portion 162 has concaves and convexes including the concave portions 162 n recessed in the thickness direction of the plate-like portion 161, at the end portion which is far from the plate-like portion 161.

It should be noted that the peripheral wall portion 162 is not limited to be provided with the concave portions 162 n, and may be provided with convex portions protruding in the thickness direction of the plate-like portion 161, at the end portion of the peripheral wall portion 162 which is far from the plate-like portion 161. That is, the peripheral wall portion 162 may have concaves and convexes including the convex portions protruding in the thickness direction of the plate-like portion 161, at the end portion which is far from the plate-like portion 161. Further, the peripheral wall portion 162 may have concaves and convexes including both the concave portions 162 n recessed in the thickness direction of the plate-like portion 161 and the convex portions protruding in the thickness direction of the plate-like portion 161, at the end portion which is far from the plate-like portion 161.

In the present embodiment, a plurality of concave portions 162 n are provided in the first peripheral wall portion 162 c, to be spaced from each other. Further, one concave portion 162 n is provided in the long side of the rectangular portion 161 r.

As shown in FIG. 3, the resin portion 170 covers the frame portion 160 to surround the surfaces of the frame portion 160. The resin portion 170 enters the concave portions 162 n provided in the first to fourth peripheral wall portions 162 c, 162 r, 162 p, 162 q.

Here, the function of the concaves and convexes provided in the peripheral wall portion 162 will be described. The resin portion 170, which is arranged at a position where movement of the resin portion 170 is restricted by the frame portion 160 when the resin portion 170 thermally expands, is subjected to a high thermal stress.

Positions where movement of the resin portion 170 is restricted by the frame portion 160 when the resin portion 170 thermally expands in accordance with the present embodiment are the circumference of the first protruding portion 163, the circumference of the second protruding portion 164, the inside of the three counterbored portions 165, the circumference of a first connection portion 1621between the first peripheral wall portion 162 c and the third peripheral wall portion 162 p, the circumference of a second connection portion 1622 between the first peripheral wall portion 162 c and the fourth peripheral wall portion 162 q, and the inside of the concave portions 162 n. It should be noted that the position where movement of the resin portion 170 is restricted by the frame portion 160 when the resin portion 170 thermally expands will be described below as a stress concentration position.

The thermal stress which acts on the resin portion 170 arranged at the stress concentration position is dispersed if there is another stress concentration position in the vicinity, and is increased with an increase in the interval between the stress concentration positions adjacent to each other. Since the peripheral wall portion of the bottomed cylindrical cover is originally a portion to be connected to another member in order to ensure a space between the cover and the other member, a stress concentration position is less likely to be formed in the peripheral wall portion. On the other hand, in the case of the cover 150 of the electric compressor 100, as the shape of the cover 150 is matched to the outer shape of the housing 110, the first and second connection portions 162 b1, 162b 2 may be formed in the peripheral wall portion 162, and if there is a large interval between the first connection portion 162 b1 and the second connection portion 162 b2, a high thermal stress acts on the resin portion 170 arranged in the circumference of the first and second connection portions 162 b 1, 162 b 2.

Thus, in the electric compressor 100 in accordance with the present embodiment, the concave portion 162 n is provided in each of the first peripheral wall portion 162 c and the second peripheral wall portion 162 r between the first connection portion 162 1 and the second connection portion 162 b 2. The resin portion 170 is engaged with the concaves and convexes. This can suppress the thermal stress which acts on the resin portion 170 arranged in the circumference of the first and second connection portions 162 b 1, 162 b 2, and can suppress breakage of the resin portion 170. Further, formation of the stress concentration positions in the vicinity of the first protruding portion 163 and the second protruding portion 164 can suppress the thermal stress which acts on the resin portion 170 arranged in the circumference of the first protruding portion 163 and on the resin portion 170 arranged in the circumference of the second protruding portion 164.

Therefore, the thickness of the resin portion 170 can be reduced, and as a result, downsizing, weight saving, and cost reduction of the electric compressor 100 can be achieved.

FIG. 6 is a side view showing a shape of an end portion of a peripheral wall portion of a frame portion of a cover included in an electric compressor in accordance with a modification of the first embodiment of the present invention. As shown in FIG. 6, in the modification of the present embodiment, concaves and convexes including both the concave portions 162 n recessed in the thickness direction of the plate-like portion 161 and convex portions 162 t protruding in the thickness direction of the plate-like portion 161 are provided continuously in the peripheral wall portion 162, at an end portion which is far from the plate-like portion 161. In this case, the thermal stress which acts on the resin portion 170 can be further dispersed, and local concentration of the thermal stress can be suppressed. From the viewpoint of dispersing the thermal stress, the concaves and convexes are preferably provided continuously along the entire perimeter of the peripheral wall portion 162.

Hereinafter, an electric compressor in accordance with a second embodiment of the present invention will be described. It should be noted that, since the electric compressor in accordance with the present embodiment is different from the electric compressor 100 in accordance with the first embodiment only in the shapes of the plate-like portion and the peripheral wall portion of the frame portion of the cover, the description of other components will not be repeated.

Second Embodiment

FIG. 7 is a bottom view showing an appearance of a frame portion of a cover included in the electric compressor in accordance with the second embodiment of the present invention. As shown in FIG. 7, a frame portion 260 of the cover included in the electric compressor in accordance with the second embodiment of the present invention includes a plate-like portion 261 in the shape of a flat plate, a peripheral wall portion 262 extending from an outer peripheral edge of the plate-like portion 261 toward the housing, and a tubular first protruding portion 263 and a tubular second protruding portion 264 protruding from a surface of the plate-like portion 261 opposite to a surface thereof provided with the peripheral wall portion 262. The plate-like portion 261 in accordance with the present embodiment has a configuration in which concave and convex portions are provided in an outer peripheral edge of a circular plate member.

Since the peripheral wall portion 262 extends from the outer peripheral edge of the plate-like portion 261 toward the housing, it has a wavy shape. Thereby, concave and convex portions 262 m are provided continuously along the entire perimeter of the peripheral wall portion 262, although the concave and convex portions 262 m may be provided only partially in the peripheral wall portion 262. From the viewpoint of dispersing the thermal stress, however, the concave and convex portions 262 m are preferably provided continuously along the entire perimeter of the peripheral wall portion 262.

A plurality of concave portions 262 n are provided at an end portion of the peripheral wall portion 262 which is far from the plate-like portion 261. In the present embodiment, each concave portion 262 n is formed by providing a notch in the end portion which is far from the plate-like portion 261, utilizing the wavy shape of the concave and convex portions 262 m. That is, the peripheral wall portion 262 has concaves and convexes including the concave portions 262 n recessed in a thickness direction of the plate-like portion 261, at the end portion which is far from the plate-like portion 261.

It should be noted that the peripheral wall portion 262 is not limited to be provided with the concave portions 262 n, and may be provided with convex portions protruding in the thickness direction of the plate-like portion 261, at the end portion of the peripheral wall portion 262 which is far from the plate-like portion 261. That is, the peripheral wall portion 262 may have concaves and convexes including the convex portions protruding in the thickness direction of the plate-like portion 261, at the end portion which is far from the plate-like portion 261. Further, the peripheral wall portion 262 may have concaves and convexes including both the concave portions 262 n recessed in the thickness direction of the plate-like portion 261 and the convex portions protruding in the thickness direction of the plate-like portion 261, at the end portion which is far from the plate-like portion 261.

In the electric compressor in accordance with the present embodiment, the peripheral wall portion 262 is formed in a wavy shape, and the plurality of concave portions 262 n are provided at the end portion of the peripheral wall portion 262 which is far from the plate-like portion 261. Accordingly, the distance between the stress concentration positions can be further reduced. As a result, the thermal stress which acts on the resin portion can be dispersed, and local concentration of the thermal stress can be suppressed. Thus, the thermal stress which acts on the resin portion can be reduced to be equal to or lower than an allowable stress, and breakage of the resin portion can be suppressed.

Thereby, the thickness of the resin portion can be reduced. As a result, downsizing, weight saving, and cost reduction of the electric compressor can be achieved. It should be noted that the concave and convex portions 262 m in accordance with the present embodiment may be applied to the peripheral wall portion 162 in accordance with the first embodiment.

Although the embodiments of the present invention have been described, it should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the scope of the claims, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims. 

What is claimed is:
 1. An electric compressor, comprising: a compression mechanism for compressing a fluid; an electric motor for driving the compression mechanism; an inverter for driving the electric motor; a housing for accommodating the compression mechanism and the electric motor; and a cover attached to the housing to accommodate the inverter between the cover and the housing, wherein the cover is constituted of a metal frame portion and a resin portion covering the frame portion to surround surfaces of the frame portion, the frame portion has a plate-like portion and a peripheral wall portion extending from an outer peripheral edge of the plate-like portion toward the housing, the peripheral wall portion has concaves and convexes including at least one of a concave portion recessed in a thickness direction of the plate-like portion and a convex portion protruding in the thickness direction of the plate-like portion, at an end portion which is far from the plate-like portion, and the resin portion is engaged with the concaves and convexes.
 2. The electric compressor according to claim 1, wherein the concaves and convexes are provided continuously.
 3. The electric compressor according to claim 2, wherein the concaves and convexes are provided continuously along an entire perimeter of the peripheral wall portion.
 4. The electric compressor according to claim 1, wherein the peripheral wall portion includes concave and convex portions provided continuously when viewed in the thickness direction of the plate-like portion.
 5. The electric compressor according to claim 4, wherein the concave and convex portions are provided continuously along an entire perimeter of the peripheral wall portion. 